John Zorn was born September 2, 1953, in Queens, New York, to a hairdresser father and a mother who taught education; his father had immigrated as a child to Astoria, and the family settled in the Utopia section of Queens. Both parents were serious music listeners — his mother favored classical music, his father jazz and French popular song — and a young Zorn absorbed his older brother's doo-wop and rock and roll records on top of it. He started piano at seven and added guitar and flute by ten. The catalyzing moment came at nine, when he saw Sergio Leone's A Fistful of Dollars and became fixated on Ennio Morricone's score — an obsession with film music and with the act of composing for images that would resurface two decades later as his breakout record. He attended the United Nations International School in Manhattan, began composition lessons with Leonardo Balada at fourteen, and by the time he enrolled at Webster College (now Webster University) in St. Louis, Missouri, had already found free jazz; hearing Anthony Braxton's solo saxophone record For Alto there pushed him to switch from other instruments to the horn that would become his voice. He dropped out and moved to Manhattan, giving concerts in his small apartment using reeds, duck calls, and tape manipulation — as much a laboratory as a performance space.

Through the late 1970s and early 1980s, Zorn built a body of "game pieces" — structured-improvisation works for ensembles of downtown musicians, governed by rulebooks rather than fixed notation. Pool (1980), Archery (1981), Lacrosse and Hockey (both drafted in this period), and Cobra (completed October 9, 1984, and first documented on record in 1987) used sports- and game-derived names and a system of hand signals, relayed through a "prompter," to cue solos, style and volume changes, and section breaks — telling players when to play and with whom, without dictating what to play. The approach let Zorn harness the extended-technique vocabulary the downtown scene was developing without boxing it into fixed composition, and it became one of his most influential and widely taught contributions to the music.

Zorn's wider reputation arrived in 1985 with The Big Gundown (Nonesuch), an album of radically rearranged Morricone film themes — a full-circle return to the music that had fixated him as a nine-year-old, filtered through a downtown cast of players and turned into one of the most acclaimed jazz records of the decade. Spillane (1987), built around hard-boiled noir atmosphere and a "file-card" compositional method, extended the same idea of genre-collage-as-composition. In 1988 he formed Naked City with Bill Frisell (guitar), Fred Frith (bass), Wayne Horvitz (keyboards), and Joey Baron (drums), later joined on record by Yamatsuka Eye of the Japanese noise group Boredoms on vocals. The band's self-titled 1990 debut and the albums that followed — Torture Garden (1990), Grand Guignol (1992), Heretic: Jeux Des Dames Cruelles (1992), Absinthe and Radio (1993) — collapsed hardcore, grindcore, surf, and free jazz into songs sometimes only seconds long, drawing directly on bands like Napalm Death and Agnostic Front and helping widen jazz's audience into the punk and metal underground. A parallel power trio, Painkiller, paired Zorn with bassist/producer Bill Laswell and Napalm Death drummer Mick Harris for a similarly extreme, grindcore-inflected take on free improvisation.

The pivot that defined the second half of his career came in 1993. Approaching forty, Zorn later said he arrived at the idea that the essence of Jewish identity was its outsider status, and set out to write joyful music from that insight rather than treat Jewish tradition as something to preserve behind glass. He formed Masada — named for the mountain fortress where, according to tradition, a besieged Jewish community chose death over Roman submission — as a quartet with himself on alto sax, trumpeter Dave Douglas, bassist Greg Cohen, and drummer Joey Baron, debuting at the Knitting Factory on September 12, 1993. Over the following two decades Zorn composed 613 tunes for the project — matching the traditional count of mitzvot, or commandments, in the Torah — organized into three songbooks: the original Masada Book One (205 tunes, 1993–2005, recorded across ten quartet albums released alphabetically by Hebrew letter, Alef through Yod, on DIW and then Tzadik), Book Two (The Book of Angels, 2004, 316 tunes distributed to more than twenty different musicians and ensembles for over two dozen Tzadik recordings), and Book Three (The Book Beri'ah, completed in 2014 and released as an 11-disc Tzadik box set in 2018). The quartet's book was also reworked by chamber and electric offshoots — the strings-and-clarinets ensemble Bar Kokhba (1996) and the amplified, groove-driven Electric Masada — and by a New Masada Quartet that Zorn has continued recording into the 2020s.

In 1995, working with engineer and producer Kazunori Sugiyama, Zorn founded Tzadik Records to keep his own sprawling catalog in print and to give a home to experimental musicians who struggled to release music through conventional labels. Tzadik's Radical Jewish Culture series alone has issued close to 200 titles exploring Jewish musical identity, alongside imprints for new classical composition, Japanese underground music, and women in experimental composition; the label also houses Zorn's ongoing Filmworks series (documenting more than two dozen film and documentary scores since 1986) and his solo pipe-organ recordings, the Hermetic Organ series, recorded in cathedrals and concert halls worldwide. Zorn also founded and serves as artistic director of The Stone, the East Village performance space dedicated to experimental music. In 2006 the MacArthur Foundation named him a Fellow, awarding its "genius grant" and citing him as a largely self-taught artist who, since the mid-1970s, has stood at the center of New York's downtown music scene.

Zorn's output shows no sign of slowing in his seventies: Discogs credits him as the lead artist on well over 300 releases, the overwhelming majority on Tzadik since the mid-1990s, including new volumes of the Bagatelles and Hermetic Organ series and further New Masada Quartet recordings released as recently as 2024–2026. He remains, by any measure, one of the most prolific and category-defying composers in American music — as comfortable writing a chamber work for string quartet as he is fronting a grindcore trio or reworking klezmer melody into a saxophone quartet.

Zorn's career-long refusal to settle into a single genre — moving fluidly between free jazz, hardcore, klezmer-rooted composition, and film-score pastiche — made him one of the most restlessly inventive figures in American experimental music. Two structural ideas run underneath nearly everything he's made: the game piece, which treats improvisation as something that can be organized by explicit rules rather than fixed notation or entirely free blowing, and the songbook, which lets a single body of melodic material (most famously the 613 Masada tunes) be reinterpreted across wildly different instrumentations and ensembles. His early absorption of Ennio Morricone's film scoring and Anthony Braxton's extended saxophone vocabulary set the poles his music has swung between ever since — cinematic, referential collage on one end, and raw, technique-driven improvisation on the other. Naked City and Painkiller pulled hardcore punk and grindcore directly into that mix, drawing on Napalm Death and Agnostic Front as seriously as on bebop or Morricone. Masada, by contrast, pulled in the opposite direction: a 1993 realization that Jewish identity's outsider status was itself something to celebrate, rather than mourn, launched two decades of klezmer-rooted composition that treated Ashkenazi melody as living material for a jazz quartet rather than museum repertoire. Tzadik Records, founded in 1995, became the infrastructure that let Zorn and an entire generation of downtown New York improvisers keep releasing music that didn't fit conventional label categories — the clearest evidence of how much of Zorn's influence runs through the community he built as much as through his own catalog.